Referring to FIG. 1, a flow diagram of a conventional transport channel multiplexing process 20 is shown. The processes 20 is used to transmit a radio frame in a downlink of a 3rd Generation Partnership Project system. The system specifies binary data bits and indication bits for a discontinuous transmission (i.e., DTX) state. The indication bits with the DTX state are used to fill non-data portions of the radio frame. Insertion points of the DTX indication bits (i.e., 1st Insertion of DTX Indication block and 2nd Insertion of DTX Indication block) depend on modes of the transport channels used in the radio frame. The system decides which modes are used during a connection.
In practice, adding the DTX indication bits to the radio frame means switching from working with one-bit symbols to working with two-or-more-bit symbols. The larger symbols are used to distinguish the DTX indication bits from the data bits. Working with greater than one-bit symbols effects a processing power used by the transport channel. Where no DTX indication bits are present in a radio frame, all of the processing power can work on only data bits. Furthermore, the data bits can be saved in a packed way (i.e., eight data bits packed into a byte) and can be handled in parallel. Where the DTX indication bits are added to the radio frame, the data bits and the DTX indication bits are distinguished by representing each with multiple bits.
Conventional approaches distinguish the data bits from the DTX indication bits by saving each data bit in either a 2-bit symbol or an 8-bit symbol. The conventional approaches cause degradation in the processing power due to the extra bits. By representing each data bit with an N-bit symbol, the transport channel works on N times as many bits to support three states. An example of conventional 2-bit symbols approach is illustrated in Table I as follows:
TABLE IBitsSymbols with DTX000101DTX10
It would be desirable to implement discontinuous transmission in a frame comprising single-bit symbols.